The identification of interesting proteins within the CNS utilizing 2-dimensional gel electrophoresis (2DE) continues. 1) We have isolated and purified a soluble protein designated "protein 38" which is found in the rat brain as one of the protein spots appearing on the 2DE gels. Protein 38 has a molecular weight of 57 kD (dimer) and 28.6 kD (monomer). Immunocytochemical studies using an antibody raised to this protein revealed that protein 38 is localizated in capillary endothelial cells in the brain and periphery. Cell cultures derived from newborn rat cortices revealed positive staining of stress fibers within endothelial cells. 2) A second study involves the isolation, partial purification and immunohistochemical localization of a 94 kD phosphoprotein ("protein 94"). This cytosolic protein has been partially purified from the bovine caudate nucleus. Purification was monitored by autoradiography of 32P-phosphorylated samples separated by SDS-PAGE. A rabbit antibody to this protein was used for a study of the immunohistochemical localization of this protein in cell cultures of astroglia of newborn rat cortices and revealed a single type of cell which has been tentatively identified as microglia. 3) Studies of proteins within auditory nuclei indicated one protein (MW = 29 kD, pI = 5.3) which is highly localized in the cochlear nuclei in rabbits, rats and guinea pigs.